1. Field of the Invention
The present invention relates to a light emitting element having a plurality of cells, and more particularly, to a light emitting element having a plurality of vertical light emitting cells arranged on a single substrate.
2. Discussion of the Background
A light emitting diode (LED) is an element in which minority carriers (electrons or holes) injected using a P-N junction structure of a semiconductor are produced and certain light is emitted through recombination of the carriers. Such an LED is used as a display element or a backlight. Recently, studies have been actively conducted to apply the LED to general illumination.
As such, an LED applied to general illumination consumes less electrical power and has a longer lifespan as compared with conventional light bulbs or fluorescent lamps. That is, since the LED consumes several to several tens of times less power and has several to several tens of times longer lifespan than the conventional illumination devices, it is further superior in view of power saving and durability.
Generally, in order to use an LED for the purpose of illumination, the LED is manufactured in the form of a lamp by forming light emitting elements through an additional packaging process, connecting a plurality of the light emitting elements in series through wire bonding, and installing a protection circuit, an alternating current/direct current (AC/DC) converter and the like at the outside of the light emitting elements.
FIG. 1 is a conceptual diagram showing a conventional light emitting apparatus.
Referring to FIG. 1, a light emitting apparatus for general illumination is manufactured by serially connecting a plurality of light emitting elements 1 on which light emitting chips are respectively mounted. To this end, the plurality of light emitting elements 1 are arrayed in series, and the light emitting chips within different light emitting elements 1 are then electrically connected in series through a metal wiring process. Such a manufacturing process is disclosed in U.S. Pat. No. 5,463,280. However, if a light emitting apparatus for general illumination is manufactured based on the conventional technique, there is a problem in that the metal wiring process is performed on a large number of light emitting elements 1 one by one so that processing steps are increased in number and complicated. As the number of the processing steps is increased, a percent defective also increases, thereby inhibiting mass production. Further, there may be a case where the metal wiring is short circuited due to a certain shock and the operations of light emitting elements 1 are stopped. Furthermore, if the respective light emitting elements 1 are connected in series, there is a disadvantage in that spaces occupied by the light emitting elements 1 are expanded, so that a lamp becomes considerably voluminous.
A wafer level array of microchips rather than the element level array of light emitting chips described above is disclosed in Korean Patent Laid-Open Publication No. 2004-9818. This relates to a display apparatus, wherein light emitting cells are arranged in a matrix form such that LEDs for inducing luminescence are disposed at respective pixels. However, since different electrical signals should be applied in respective vertical and horizontal directions and also in an address manner to allow the elements arranged in the matrix form to emit light, they are extremely difficult to control. Further, wiring may be disconnected due to the array in a matrix form, and a great deal of interference occurs in an area where wires overlap with one another. Furthermore, there is a problem in that the aforementioned structure in a matrix form is not applicable to a light emitting apparatus for illumination to which a high voltage is applied.